Power printed circuit boards have many applications in the field of power electronics, and especially in the automotive field. They may for example be used in converters for electrical traction devices.
A printed circuit board generally includes an insulating substrate, for example made of glass epoxy, bearing a conductive layer, for example made of copper, in which the conductive tracks of an electronic or electrical circuit are produced. To pass high currents through these tracks, it may be envisioned to increase the width and/or thickness of these tracks. However, this is sometimes not enough or incompatible with the required size of the circuit. Another solution consists in using a plate or grille of electrically conductive material (the lead frame) or a bus bar connected to the tracks of the printed circuit board. This connection may be made by screwing, brazing, press-fitting, chemical deposition of copper (vias), or welding. A plurality of types of welding are envisioned in document WO 2009/121697 A1, such as soldering with a solder or laser welding.